Check again all pipes about turbo for leaks,,,specially "T" pieces in system... I had same problem. You can easyly check you amal valve for working, unplug one side of pipe...connect 12V to amal valve (from battery) and make some pressure to pipe. You can test it if its working. (I am guessing that amal valve will be ok)

What chip you have in car? What ECU and what config of engine? Turbo, injectors...etc. Do you have vacuum on idle (on turbo pressure gauge)? When you "fast - softly" pull the accelerator pressure gauge must jump up to 0 bar for second. (If you have leaks, it will not jump to 0 bar, ).

Finally when there is a leak in the system turbo is charging pressure for a long time... car is little bit "lazy" up to 2500 - 3000 rpm.